vip21-javaweb/day03/src/Jdbc.java

import java.sql.*;

public class Jdbc {

    public static void main(String[] args) {
        try {
            prep1();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public static void prep1() throws ClassNotFoundException, SQLException {

        Class.forName("com.mysql.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/vip21?autoReconnect=true&failOverReadOnly=false&useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=false&serverTimezone=GMT%2B8";
        String user = "root";
        String passwd = "123456";

        String username = "1 OR 1 = 1";
        String password = "123456";

        Connection connection = DriverManager.getConnection(url, user, passwd);
        String sql = "SELECT * FROM tb_users WHERE username = ? LIMIT 1"; //MYSQL 服务器会把这个SQL 编译成2进制
        PreparedStatement preparedStatement = connection.prepareStatement(sql);
        preparedStatement.setString( 1, username );
        ResultSet resultSet = preparedStatement.executeQuery();

        while ( resultSet.next() ) {
            String password1 = resultSet.getString("password");
            if ( password1.equals(password) ) {
                System.out.println( "用户登陆成功" );
                return ;
            }
        }

        System.out.println( "用户登陆失败" );

    }


    public static void resultSet() throws ClassNotFoundException, SQLException {

        Class.forName("com.mysql.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/vip21?autoReconnect=true&failOverReadOnly=false&useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=false&serverTimezone=GMT%2B8";
        String user = "root";
        String passwd = "123456";
        String id = "3";
        Connection connection = DriverManager.getConnection(url, user, passwd);
        Statement statement = connection.createStatement();
        String sql = "SELECT * FROM tb_brand WHERE id = " + id;
        ResultSet resultSet = statement.executeQuery(sql);

        while ( resultSet.next() ) {
            System.out.println( resultSet.getInt("id") );
            System.out.println( resultSet.getString("brand_name") );
            System.out.println( resultSet.getString("company_name") );
            System.out.println( resultSet.getString("description") );
        }


        //System.out.println( resultSet );

    }

    public static void prep() throws ClassNotFoundException, SQLException {

        Class.forName("com.mysql.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/vip21?autoReconnect=true&failOverReadOnly=false&useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=false&serverTimezone=GMT%2B8";
        String user = "root";
        String passwd = "123456";

        String username = "1 OR 1 = 1";
        String password = "123456";

        Connection connection = DriverManager.getConnection(url, user, passwd);
        Statement statement = connection.createStatement();
        String sql = "SELECT * FROM tb_users WHERE username = " + username + " LIMIT 1";
        ResultSet resultSet = statement.executeQuery(sql);

        while ( resultSet.next() ) {
            String password1 = resultSet.getString("password");
            if ( password1.equals(password) ) {
                System.out.println( "用户登陆成功" );
                return ;
            }
        }

        System.out.println( "用户登陆失败" );

    }

    public static void Jdbc() throws ClassNotFoundException, SQLException {

        Class.forName("com.mysql.jdbc.Driver");

        String url = "jdbc:mysql://localhost:3306/test?autoReconnect=true&failOverReadOnly=false&useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=convertToNull&useSSL=false&serverTimezone=GMT%2B8";
        String user = "root";
        String passwd = "123456";
        Connection connection = DriverManager.getConnection(url, user, passwd);
        connection.setAutoCommit(false);
        Statement statement = connection.createStatement();
        String sql = "INSERT INTO `t` (`name`, `age`) VALUES ('李四', 22)";
        int i = statement.executeUpdate(sql);
        connection.commit();
        System.out.println( i );
    }

}